Abstract
We have developed a selective, sensitive, and re-usable electrochemical sensor for Hg2+ ion detection. This sensor is based on the Hg2+-induced conformational change of a single-stranded DNA (ssDNA) which involves an electroactive, ferrocene-labeled DNA hairpin structure and provides strategically the selective binding of a thymine-thymine mismatch for the Hg2+ ion. The ferrocene-labeled DNA is self-assembled through S-Au bonding on a polycrystalline gold electrode surface and the surface blocked with 3-mercapto-1-propanol to form a mixed monolayer. The modified electrode showed a voltammetric signal due to a one-step redox reaction of the surface-confined ferrocenyl moiety. The 'signal-on' upon mercury binding could be attributed to a change in the conformation of ferrocene-labeled DNA from an open structure to a restricted hairpin structure. The differential pulse voltammetry (DPV) of the modified electrode showed a linear response of the ferrocene oxidation signal with increase of Hg2+ concentration in the range between 0.1 and 2 microM with a detection limit of 0.1 microM. The molecular beacon mercury(II) ion sensor was amenable to regeneration by simply unfolding the ferrocene-labeled DNA in 10 microM cysteine, and could be regenerated with no loss in signal gain upon subsequent mercury(II) ion binding.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.